/*
  (c) Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Hewlett-Packard Development Company, LP
  [See end of file]
  $Id: Pipe.java,v 1.1 2009/06/29 08:55:45 castagna Exp $
*/

package com.hp.hpl.jena.graph.query;

/**
    A Pipe is anything that can be used to get and put Domain objects; it can be 
    closed, and it can be tested for whether more elements are available. A pipe 
    may be closed with an exception, in which case hasNext/get will fail with that 
    exception when they are called.
    
	@author kers
*/
public interface Pipe
    {
    /**
        Answer true iff there are more elements for <code>get()</code> to get. If
        the pipe was closed with an exception, throw that exception.
    */
    public boolean hasNext();
    
    /**
        Answer the next element if there is one, otherwise throw a NoSuchElementException.
     */
    public Domain get();
    
    /**
        Put a domain element into the pipe for later extraction.
    */
    public void put( Domain d );
    
    /**
        Close the pipe. hasNext() will deliver <code>false</code>, and 
        <code>get</code> will throw an exception.
    */
    public void close();
    
    /**
         Close the pipe (see close()) and record <code>e</code> as its termination
         status. Any <code>get</code> from the pipe must then fail, throwing an
         exception.
         
         @param e the exception that caused the pipe to be closed
    */
    public void close( Exception e );
    }

/*
    (c) Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Hewlett-Packard Development Company, LP
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    3. The name of the author may not be used to endorse or promote products
       derived from this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
